All year air conditioning system



Jan. 10, 1939. s. D. KINGSLAND ET AL ALL YEARAIR' CONDITIONING SYSTEI 2 Sheets-Sheet 1 Filed June 6, 1934 -Zf-I-I-E: mi

Qwomtou I GeorgeD.Kingeland JoaephE-Robb Filed June is, 1934 Jvwmtoc M v we 4, 9w nn v 7 32. w oi N 3N =9 0 nom New H N w 1 2 Sheets-Sheet 2 George D; Kingaland Joseph E. Robb Jan. 10, 1939; e. D. KINGSLAND ET AL ALL YEAR AIR CONDITIONING SYSTEI Patented Jam. 10, 1939 UNITED STATES PATENT OFFICE ALL rm AIR CONDITIONING srs'rsu George D. Ki

d, Minneapolis, Minn, and

Application June 8, 1934, Serial No. 729,252

, 20 Claims.

The present invention relates to an improved air conditioning system for all-year operation by means of which a space or building is cooled in the summer andis heated and humidified in the winter.

One of the objects of the present invention is the provision of an air conditioning system including steam operated heating means and steam operated cooling means which are supplied with steam from a single boiler or steam generator under the control of suitable thermostatic mechanism. The steam operated heating means preferably takes the form of steam radiators or heat ing coils and the steam operated cooling means is preferably in the form of a steam jet injector type of cooling apparatus.

Another object of the invention is the provision of an improved temperature changing system in which a temperature changer is operable to change the temperature in two different spaces, the temperature changer being controlled by the temperature prevailing in one of the spaces and the effect of the temperature changer on both of said spaces being controlled by a thermostat responsive to the temperature prevailing in the other of the spaces. In the preferred form of this phase of the invention, a temperature changer is intermittently operated by a thermostat located in one space and servesto heat a supply of air which is circulated to both of the spaces. A thermostat located in the other of the spaces serves to control the proportions of this circulated air which is circulated to each of the spaces.

A further object of the invention is the provision of an improved temperature control system for summer-winter operation by which the supply of outdoor air to a space to be controlled is varied from a minimum to a maximum and then again to a minimum upon a change in temperature in one direction during the summer and is varied only from a minimum to a maximum upon temperature changes in a single direction during the winter. In the preferred form ofthe invention, both of these thermostats are outdoor thermostats, the arrangement being such that in the summer the outdoor air is varied from a minimum to a maximum as the outdoor temperature raises from a value lower than that desired within the space to be controlled to the value desired in the controlled space and is then again I reduced to a minimum as the outdoor temperamating the desired indoor temperature to a more severe outdoor temperature condition.

Another object oi the invention is the provision of an improved system of control for a steam operated cooling means. 1

A further object ofthe invention is the provi sion of an improved heating system.

Further objects of the invention include the various features and functions of the system as a whole as well as the various features and functions of the various sub-combinations and parts thereof.

Other objects of the invention will be found in the detailed descriptiomin the drawings, and in the appended claims.

For a better understanding of the invention, reference may be had to the following description and accompanying drawings, in which;

Fig. 1 is a diagrammatic showing of the complete control system, and

Fig. 2 is a diagrammatic showing of the control systems for the inlet air dampers and for the outlet air damper.

Referring first to Fig. l of the drawings, the system includes an air conditioning device, generally indicated at 10, which includes an air conditioning chamber ll. Located in the air conditioning chamber H is a preheating coil I2 and a reheating coil l3 which are supplied with steam from a steam boiler H by means of a pipe I5. A hand-operated shut-off valve I6 is located in pipe and may be utilized to prevent the flow of steam to the preheating and reheating coils l2 and I3 during the summer time. The flow of steam to the preheating coil i2 is additionally controlled by means of an electrically operated valve 9 in a manner to be hereinafter described.

The boiler I4 is fired by a gas burner I! which, in turn, is controlled by an electrically operated gas valve it that controls the flow of gas from a gas supply pipe l9 to the burner H. A pilot burner 20, which is normally constantly burning, is supplied with gas by means of a pilot pipe 20a which communicates with the gas supply pipe I! in front of the electrically operated gas valve II. The primary controls for the gas valve ll comprise a room thermostat 2| and an outdoor thermostat i2 herein indicated diagrammatically by mercury switches of well-known construction. The room thermostat 2| is provided with a pair of contacts 23 which close when the room temperature is at or below some predetermined minimum temperature. say 70 F. This room thermmtat II is additionally provided with a second pair of contacts 24 which are closed when the room temperature is at or above said predetermined minimum temperature. The cold contacts 23 of the room thermostat M are the primary control for the gas valve l8 when the apparatus is operating on the winter cycle as will hereinafter become evident whereas the hot contacts 24 thereof are the primary control for gas valve is when the apparatus is operating on the summer cycle.

The outdoor thermostat 22 is provided with a single pair of contacts 25 which open when the outdoor temperature decreases below the desired room or space temperature. A'single pole, dou ble throw manually operable summer-winter switch comprises a switch arm 26, a winter contact 8'! and a summer contact 28. The two thermostats 2i and 22 and this summer-winter switch cooperate in the control of a relay generally into the position shown in the drawings, switch arms 32 and move from engagement with contacts 34 and 35 and switch arm 32 moves into engagement with contact 33. Power for relay 29 is supplied by the low voltage secondary 3? of a step-down transformer 38, having a high voltage primary 39 connected to suitable line Wires. The

gas valve is is additionally controlled by another relay, generally indicated at til, which comprises an energizingcoil Qi and a bucking coil 62 that cooperate in the control of an armature 3.

When armature 63 is attracted, it moves a pair of switch arms ts and 35 into engagement with a pair of cooperating contacts as and it, these switch arms being out of engagement with contacts 43 and 3? when the armature so is in its normal unattracted position. The relay 29 contributes to the control of relay 66 which is also controlled by a. high limit pressure control generally indicated at it. This high limit pressure control comprises a pressure responsive element in the form of a bellows so which is connected to the steam pipe i5. Bellows d9 operates a pivoted switch carrier to which supports a mercury switch 5%. The mercury switch 5! is provided with a pair of low pressure contacts 52 which are closed when the pressure is low and with a pair of high pressure contacts 53 which are closed when the pressure is high. This pressureresponsive high limit control may take the form shown in Louis A. M. Phelan Patent No 1,736,129

which issued November 29, 1929, and is preferably adjusted so the high pressure contacts 53 are closed when the pressure in steam boilerifi attains some excessive value such as 15 lbs. per square inch. The low pressure contacts 52 are preferably arranged to operate at some slightly lower value so there is a differential between the operation of the high and low pressure contacts.

Power for relay 40 is supplied by the low voltage secondary 54 of a step down transformer 55, having a high voltage primary 56. The, flow of power to the transformer 55 is controlled, among other things, by a switch 5! which responds to the water level in the boiler in the usual and wellknown manner. The pilot 2!? is preferably pro vided with a safety device in the form of a bimetallicthermostatic element 58 which engages a cooperating contact 59, whenever the pilot 28 is burning. This safety pilot comprised by element 5B and contact 59 also contributes to the control of gas valve E8.

The air conditioning chamber ii is further provided with a. cooling coil 60 which is supplied with a cooling medium that is cooled by means of a steam jet injector, generally indicated at 6|. This fluid medium is transmitted from the steam jet injector 6! to the cooling coil 68 by means of pipes 62, 53 and 54 and by means of an electrically operated circulating pump 55. Energization of circulating pump '65 is controlled by a relay 66 which comprises a relay coil 61 and an armature 68 that moves a switch arm 69 into engagement with a contact 10 when the relay coil 51 is energized.

Air is circulated through the air conditioning device so by means of an electrically operated blower I t. This blower is controlled by a relay 12 which includes a relay coil 73, and an armature it that controls the movements of a switch arm it which cooperates with a contact 16. The relay i2 is controlled by means of a time switch Hand a pressure responsive switch It.

The time switch ii comprises a motor having an energizing winding 19 which operates a cam 86 through suitable "reduction gearing (not shown). The cam operates a pivoted switch carrier 8| that in turn rsupports a mercury switch 82. The arrangement is such that mercury switch 82 is closed during predetermined hours of the day and is open at all other times. This time switch is herein disclosed inasmuch as the system herein illustrated has particular utility in connection with oflice buildings and the like which are generally only occupied during the day time but it will be apparent that in buildings of other types where it is desired to condition ll'a' in order to prevent the building from reaching too. low a temperaturewduring the night when the time switch 32 is opened and the system is operating on its winter cycle. This pressure responslve switching mechanism 18 includes bellows 33 which communicates with steam pipe E5 on the delivery side of shut-oil valve to. Bellows 83 operates a switch carrier 84 which in turn supports a mercury switch 85. The arrangement is such that the mercury switch 85 closes whenever the steam pressure is at or above some predetermined value say 5 lbs. per square inch. In general arrangement, this switching mechanism it may also take the form shown in the above mentioned Phelan patent.

The air conditioning chamber ii is further provided with a water spray 86 by which the air passing therethrough may be humidified. This water spray BE communicates with awater supply pipe 87 through an electrically operated water valve 88. Water valve 88 in turn is controlled,

in part, by a. humidostat 89;arranged to close explained in detail. The air conditioning device- The flow of air.

by a pressure responsive switching mechanism duct 95* leads to some special space which it is desired to control such as a recreation room in the basement, an auditorium, etc. The flow of air through these outlet ducts 94 and 95 is controlled by a mixing damper 98 which is operated in a manner, the details of which will be later disclosed.

Steam is supplied from the boiler I4 to the steam jet injector by means 01' a pipe 91 which communicates with steam pipe I5. The flow of steam through pipe 91 is controlled by an electrically operated valve 98 that is supplied with power by the secondary 99 of a step-down transformer I00, having a high voltage primary IN. This valve 98, upon being opened, lifts a lever I02 that moves a mercury switch I03 supported thereby to closed circuit position. The steam valve 98 is controlled, among other things,

I04, a low temperature responsive switching mechanism I05 and a high temperature responsive mechanism I05.

The steam pressure responsive switching mechanism I04 comprises a bellows I01 which communicates with the steam pipe 91 between the steam pipe I5 and the steam valve 98. The bellows I01 operates a switch carrier I08 that supports a mercury switch I09 having high and low pressure contacts. This pressure responsive mechanism may also take the general form shown in the above mentioned Phelan patent and is preferably adjusted so that the high pressure contacts close at about 13 lbs. steam pressure and the low pressure contacts close at approximately lbs. steam pressure.

The low temperature responsive switching mechanism I05 comprises a bellows H0 which communicates witha temperature responsive bulb III by means of a capillary tube H2. The bellows IIO, tube H2 and capsule III are charged with a suitable amount of a proper fluid as is well-knownin the art. The bellows I I0 operates a switch, support II3 which carries a mercury switch II4. This switch H4 is provided with a pair of low temperature contacts that close at some minimum safe temperature of say, 40 F. and the high temperature contacts thereof close at a temperature value slightly ,above this. The high temperature responsive switching mecha' nism I05 is similar to the low temperature responsive switching mechanism I05 andcomprises a bellows I which is connected to a capsule I2I by means of a capillary tube I22. This bellows I20 operates a switch support I23 which in turn carries a mercury switch I24. The mercury switch I24 is provided with a pair of normally open high temperature contacts that are closed upon an excessive temperature of say 100 F. The mercury switch I24 is also provided with a pair of low temperature contacts,which are normally closed and remain closed for all values below 100 F. I

The condensate formed in steam jet injector 5| flows to a condenser I from which it is removed by an ordinary electrically operated condensate or vacuum pump I3I which returns the condensate to the boiler I4 by means of a pipe I32 and also eliminates the air. The vacuum pump I3I is controlled by a relay I33 which comprises a relay coil I34 that operates an armature I35. Armature I35 controls a switch arm in which is adapted to' engage a cooperating contact I31. A vacuum responsive switching mechanism I38 comprises a bellows I39 that communicates with the interior of condenser I30. This bellows controls a switch carrier I40 which in turn supports a mercury switch MI. The arrangement is such that mercury switch I only closes when the vacuum in condenser I30 is at or below about 26 inches of mercury.

The condensor I30 is cooled by water passing through a coil I42. This water is pumped to a spray I43 by means of a spray pump I44. The water which leaves the spray I43 drops down through a cooling tower I45 and is collected at the bottom and returned to the condenser cooling coil I42 by a pipe I45. In order to increase the cooling effect of the cooling tower, it is preferably supplied with an electrically operated blower I41. Cooling tower spray pump I44 is controlled by a relay I48 which comprises a relay coil I49, an armature I50, a switch arm I5I and a cooperating contact I52. The cooling tower blower I41 is controlled by a relay I53 which comprises a relay coil I54, an armature I55, a switch arm I55, and a cooperating contact I51.

The control system for these various devices also includes a second summer-winter switch having three switch arms I 50, I5I and I52. This summer-winter switch, which is generally indicated at I53 is shown in its winter position wherein switch arm I50 engages a contact I54 and switch arm I52 engages a contact I55, it being noted that switch arm .I5I does not engage any contact whatsoever when in the winter position. It will also be noted that the switch arm I5I is permanently connected to contact I54 by a wire I55. When the summer-winter switching mechanism I53 is thrown to the summer position, switch arm I50 engages a contact I51, switch arm I5I engages a contact I58 and switch arm I52 engages a contact I59.

Turning now to Fig. 2, the damper 92 is secured to a shaft I15 which is journalled in the outdoor air inlet duct 90. A pulley I15 is secured to one extremity of shaft I15. Similarly, the damper 93, which is located in return air inlet duct 9|, is carried by a shaft I11 that is journalled in the sides of return air duct 9|. A pulley I88 is secured to the extremity of shaft I11. An inlet damper actuating mechanism generally indicated at I59 includes a vertically movable actuating rod I90 which operates an arm I9I pivoted at I92. A cable I93 has one of its ends secured to arm I 9| and is then threaded over pulleys I15 and I 88 and has its opposite end secured to a weight I94.

It will therefore be evident that when the right hand end of member I9I is moved upwardly, the pulley I15 will rotate in a clockwise direction to further close off the outdoor inlet duct 90 and the pulley I88 will be rotated in a counter-clockwise direction to more widely open return air inlet duct 9i. Upon downward movement of member I9I, thev reverse action takes place. The dampers 92 and 93, therefore, together with their controlling pulleys and cable comprise a mixing damper. When arm I9I moves to its extreme upper position, outdoor air inlet. duct 90 will be completely closed oii and return air inlet duct 9| will be completely opened. Similarly, when arm I9I moves to its intermediate position, outdoor air inlet duct 90'will be completely opened and return air inlet duct 9I will be completely closed off, the dampers 92 and 93 having moved through 90 angular degrees. When arm I9I moves to its lowermost position, outdoor air inlet duct 90 will again be completely closed oil and return air duct will be completely opened,

moves through its complete range when the system is operating on its summer cycle.

The lower end of actuating rod I96 is provided with teeth indicated at 595. These teeth cooperate with a pinion I86, carried by a shaft 19?. Shaft l9'i further carries a pair of gears E98 and E99. Gear its cooperates with a pinion 209 se cured to the rotor shaft 206 of a motor 202 which comprises a rotor 203 and a fieldwinding 2%. The gear i99 cooperates with a pinion 205 secured to the rotor shaft 206 of a motor 297 which includes a rotor 203 and a field winding 299. Shaft I97 further carries a pair of limit switch operators 2i!) and ii 8. Limit switch operator no is adapted to-operate a limit switch 282, whereas limit switch operator 2H is'adapted to operate a limit switch Zl. The shaft is? further operates a balancing contact arm 2M which is adapted to sweep across a balancing resistance 265. The arrangement is such that balancing contact arm 2M mo'ves from the extreme left hand end of v balancing resistance Eli to the extreme right hand end thereof while arm net movesfrom its lowermost position to its highest position.

The field windings 2M and 2% of motors 2d? and am are adapted to be controlled by a baianced relay mechanism which includes a switch arm 2H3. Upon movement of switch arm are in one direction, it is adapted to engage a contact 2H and upon movement in the other direction it is adapted to engage a contact 26%. Switch arm its is controlled by a plunger 29% to which it is connected by a connecting means 2%. Plunger 21s, in 'turn, is controlled by a pair of similar" be selectively controlled by a pair of potentiom in outside temperature.

eter thermostats 223 and 22$. The potentiometer thermostat 223 is the winter thermostat and responds to outdoor temperature. It comprises a bimetallic actuator 22?; which moves a contact arm 226. across a resistance 22? upon changes The range of this winter outdoor thermostat is preferably such that it moves from the extreme left hand end of resistance 227 to its extreme right hand end when the outdoor temperature decreases from approximately F.,to 20 F. The resistance 22? is wound uniformly so that equal changes in resistance are efiected by equal movements of contact arm 225. The summer outdoor thermostat 22% comprises a bimetallic actuator 228 that controls a contact arm 22%. This contact arm 229 is adapted to sweep across a resistance 2% which is wound unevenly or in a tapered fashion. The range of this instrument is preferably such that the contact arm 229 moves from the extreme left summer and winter outdoor thermostats 224 and 223 are selectively placed in control of the damper operating mechanism I89 by means of a summerwinter switch 239. This switch comprises a pair 25s, 25s and 25s.

1255 and 253.

is connected to'rheostat 239 by a wire 26E.

fiflddfidi of switch arms 232 and 233 which engage con-' tacts 23 i and 235 when in the winter position shown in Fig. 2 and engage contacts 236 and 231' when in the summer position.

Two adjusting rheostats, the utility of which will be hereinafter brought out, are indicated at 238 and 239. The rheostat 238 is shown as being in such position that practically all of its resistance is in circuit with the outdoor winter resistance 22?. With the rheostat 239 adjusted as shown, its resistance is equal to the resistance of outdoor winter rheostat 227. The combined resistance of outdoor winter resistance 22? and the operative resistance of rheostat 23b is equal to the outdoor summer resistance 23c and is also equal to the balancing resistance 28%. With the rheostat 238 adjusted as shown, none of'its resistance is in circuit with the outdoor winter resistance 22!.

Power is supplied to damper control mechanism 5-85 and its associated control devices and circuits by means of the low voltage secondary 2% of a step-down transformer 2M, having a high voltage primary 2% connected to suitable line wires. One side of secondary rat is connected to one end of field winding 2% through imit switch 292 by, means of wires 268 and 2M,

while the other side of secondary 2% is coninterconnected, their junction being indicated at 25b, The opposite or free end of solenoid 228 is connected to one side of secondary 2w by means of wires 233 and 256. This end of solenoid 228 is also connected to the left hand end of balancing resistance 2 i 5 and to rheostat 238, through a protective resistance 252, by means of wires The free end. of solenoid 2222 is connected to one side of secondary 240 by wires This same end of solenoid 222 is also connected to the right hand end of balancing resistance M5 and to switch arm 233. through a protective resistance 25?, by wires 25%, 259 and 268. Contact 235 of summer winter switch 23E It will. therefore be noted that with summer-winter switch 239 in the winter position shown, the outdoor winter resistance 22? and its series connected rheostats 238 and 23$ are in parallel with balancing resistance 25% and solenoids 225 and 222 in series, all of which are connected across the secondary 25d of transformer 2%, it being noted that protective resistances 252 and 25? are inserted between certain portions of theseparallel circuits. The junction 25d of solenoidsZZi and 222 is connected to balancing contact arm 2 the rheostat 238 by means of a wire 268. A small number of turns of solenoid MI is connected to contact 218 by a wire 289 and a small number of turns of solenoid 222 is connected to contact 2 by a wire 210.

Winter operation of inlet air dampers 92 and 93 energized and plunger 2I9 is in its mid-position wherein relay switch arm 2 I6 is disengaged from both contacts 2I1 and M6. Field windings 204 and 209 are therefore connected in series across the secondary 240 of transformer 2 by a circuit as follows: secondary 240, wire 243, wire 244, limit switch 2 l2, field winding 204, wire 241, wire 246, field winding .209, limit switch 2I3, wire 246 and wire 245 to the other side of secondary 240. The motors 202 and 201 are equally energized. These motors are arranged so that they buck one another and, since they are equally energized with the parts in the position shown, their torques will be balanced and the shaft I91 will be stationary. Arm I9I is midway between its intermediate position and its upper limit of movement. Dampers 92 and 99 are therefore in the position shown wherein equal amounts of outdoor air and return air are passed through air conditioning chamber II.

If the outdoor temperature should fall somewhat, contact arm 226 will move along resistance 221 towards the right hand end thereof. Such movement will unbalance the energizations of solenoids 22I and 222 so that solenoid 222 becomes more highly energized than solenoid 22I. Plunger 2I9 therefore moves to the right and brings relay switch arm 2I6 into engagement with contact 2". This causes the small number of turns of solenoid 222 to be placed in parallel with field winding 209 and the total flow of current through this small number of turns of solenoid 222 and through field winding 209 will traverse field winding 204 by a circuit as follows: secondary 240 of transformer 2, wire 249,- wire 244, limit switch 2| 2, field winding 204 and wire 241 at which point the circuit branches, one portion going by way of wire 249, field winding 209, limit switch 2I3 and wire 246 to wire 245 and the other side of secondary'240, whereas the other part goes by way of wire 249, relay switch arm 2I6, contact 2I1, wire 210, the small number of turns of solenoid 222 and wire 256 to wire 24 6 and the same side of secondary 240. The current flow through the small number of turns of solenoid 222 provides an additional pull on plunger 2 I9 towards the right so that relay switch arm 2I6 more firmly engages contact 2I1 and eliminates all possibility of chattering between the direction as viewed from the left and therefore rotates shaft I91 clockwise when viewed from the same direction. Balancing contact arm 2I4 will therefore travel along balancing resistance 2I6 towards the right hand end thereof. This movement of balancing contact arm 2 along balancing resistance '2I6 will gradually rebalance the energizations of solenoids22l and 222. When I the pull of solenoid 22I has thus been made equal to the combined pull' of solenoid 222 and the extra energization of its small number of turns, plunger 2I9 will be returned to its inter- I mediate position and move switch arm 2I6 from engagement with contact 2". The initial separation will be very slight, but when it has occurred the circuit through the small number of turns of solenoid 222 will be interrupted whereupon the plunger 2 I9 will move to the left a little further and relay switch arm 2l6 will again be well spaced from both contact 2 I1 and 2 I9. Separation of relay switch arm 2I6 from contact 2" again establishes the series circuit through field windings 204 and 209 whereupon motors 202 and 201 will again be equally energized and further upward movement of shaft I91 will cease. Actu-' ating rod I90 has been moved upwardly a small amount duringrthe time that balancing contact arm 2I4 traveled along balancing resistance 2I6 and this upward movement moves arm I9I closer to its upper limit allowing weight I94 to move downwardly a small amount whereby pulley I16 is rotated in a clockwise direction and pulley I99 is rotated in a counter-clockwise direction. Outdoor inlet damper 92 is therefore moved towards a vertical position and partially closes off the outdoor inlet duct 90 whereas return air damper '99 is moved towards, horizontal podtion and opens return air duct 9i more widely. In this manner, if theoutdoor temperature falls, the outdoor air inlet duct 90 is gradually closed oif and when contact arm 226 finally engages the extreme right hand end of outdoor winter resistance 221, the outdoor inlet duct 90 will be completely closed off and the return .air duct II will be completely opened.

It may be desirable to take in a small amount of outside air through outdoor inlet duct 90 at all times irrespective of how low the outdoor temperature becomes. If this action is desired, rheostat 298 may be moved from its inoperative position shown in Fig. 2 of the drawings to a position wherein a small amount of its resistance is connected in circuit with outdoor winter resistance 221. This position of rheostat 299 is illustrated in dotted lines. When this is done, there will always be a small amount of resistance between wire 266 and contact finger 226 even though the contact finger 226 engages the extreme right hand end of outdoor winter resistance 221. As a result, balancing contact arm 2 will never move to the extreme right hand end of balancing resistance H6 in order to balance the energizations of solenoids 22I and 222. Arm I9I will therefore never be moved to its extreme upper limit and outdoor air damper 92 will never move to its fullvertical position. ,In

this manner, a variable amount of outdoor air,

depending upon the adjustment of rheostat 229,

will be allowed to flow to air conditioning chamthe left, whereupon relay switch arm 2I9 is moved into engagement with contact 2". Field winding 204 and a small number of turns of solenoid 22I will therefore be placed in parallel and the full current flow through field winding 294v and the small number of turns of solenoid 22H will flow through field winding 299. This circuit is as follows? secondary 249 of transformer 24!, wire 245, wire 299, limit switch 2| 3, field winding 299, and wire 298 at which point the circuit branches, one part going by way of wire 291, field Winding 294, limit switch 212 and wire 2 t wire 249 and the other side of secondary 249,

whereas the other part goes by way of wire 249,

relay switch arm.2|6, contact 2l8, wire 269, the

small number of turns of solenoid 228 and wire 25! to wire 254 and the same side of secondary 249. Motor 291 is therefore more highly energized than motor 292 and drives motor 292 backwards. Rotor 298 of motor 291, when thus energized, rotates in a clockwise direction as viewed from the left and therefore rotates shaft i91 counter-clockwise as viewed from the same direction. Balancing contact arm 2M therefore travelsalong balancing resistance 2l5 towards the left hand end thereof until the energizations of solenoids 226 and 222 are rebalanced in the manner heretofore described for a decrease in outdoor temperature. Arm i9i is therefore moved downwardly a small amount whereupon outdoor air inlet damper 92 is moved towards its horizontal position and return air inlet dampj resistance. 221 as heretofore explained, whereas the balancing resistance N5 is equal to the combination of rheostat 239 and outdoor winter resistance 22?. Outdoor winter thermostat 233 is therefore only capable of moving arm Hi to its intermediate position wherein outdoor inlet damper 92 assumes a horizontal position and return air damper 93 is moved to its vertical position.

If it should be desired to recirculate a small amount of air even though the outdoor temperature is at or above 65 F., this can be accomplished in a manner similar to the manner in which a small amount of outdoor air can always be admitted irrespective of how low the outdoor temperature becomes by adjusting rheostat 239 to some position such as the dotted position shown in Fig. 2 wherein a little more resistance is placed in circuit with outdoor winter resistance 221. If this is done, the resistance of rheodamper 93 to its full vertical position.

From the foregoing description of the winter operation of the mixing damper comprised by '65 F. At 20 F., all return air is circulated and no" outdoor air is circulated, whereas at 65 F. all-"outdoorair and no return air is circulated. For allintennediate temperatures, a proportionof outdoor and return air is circuamassi lated. Also by proper adjustment of rheostats 238 and 239, the apparatus can be arranged so that some outdoor air will always be circulated irrespective of how low the outdoor temperature becomes and/or a small amount of return air can always be circulated irrespective of how high the outdoor temperature becomes.

, The arm l9! carries a mercury switch 215 having two pairs of contacts 216 and 211. The contacts 219 are closed whenever the arm [9| is above its horizontal position and are opened when the arm i9! moves to its horizontalposition at which time contacts 211 are closed. The contacts 219 are connected to steam valve 9 by wires 218 and 219-, whereas contacts 211 are connected to steam valve 9 by wires 219 and 289. When contacts 219 are closed, the steam valve 9 is opened and when contacts 211 are closed, the steam valve 9 is closed. Power is furnished to steam valve 9 by suitable line wires indicated at 281. Such valves and their control are well-known in the art and no further explanation is thought to be necessary at this time. It being remembered that arm 59! only reaches horizontal position during winter operation when the outdoor temperature is at or above 65 F., it will be seen that steam valve 9 is always opened to permit flow of steam to preheat coil i2 whenever the outdoor temperature is below 65 F. but if the outdoor temperature should rise to 65 F. or higher, the contacts 211 will be closed and the steam valve 9 will close so that no steam can fiow to preheat coil 82. The exact position of arm l9! atwhich steam valve 9 will be opened or closed can be varied by varying the position of mercury switch 215 in respect to the arm i9l.

Summer operation of inlet air dampers 92 and 93 For summer operationof the inlet air dampers 92 and 93,the summer-winter switch 23i is thrown to its position opposite that in which it is shown the cold end of outdoor winter resistance 221 is connected to the right hand end of balancing resistance 215. The right hand end or cold end of outdoor summer resistance 239 is connected to the right hand end of balancing resistance 2 I5. With the parts in the position shown, the contact arm 229 of outdoor summer thermostat 2 is contacting the electrical center of outdoor summer resistance 239. It being remembered that this outdoor summer resistance 239 is equal to the balancing resistance 2l5, solenoid 22! will be more highly energized than solenoid 222since balancing contact arm 2 is engaged with the balancing resistance H5 at a point midway between its center and its right hand end. Plunger 2l9 will therefore move to the left and bring switch arm 2l6 into engagement with contact 2l8 whereupon motor 291 will become more highly energized than motor 292 as heretofore explained and balancing contact arm 2 will thereby be moved along balancing resistance 2 l5 toward the left hand end thereof. When balancing contact arm 2 moves to approximately the middle of balancing resistance 2, the energizations of solenoids HI and 222 will again be balanced whereupon furthermovement of shaft I91 will cease. During this operation, arm I9! is moving downwardly to its mid position with the result that outdoor-damper 92 is moved to horizontal position and return damper 93 is moved to its vertical position.

-These positions of the parts represent a comfortable outdoor temperature of 70 F., wherein all of the air passing through'air conditioning chamber ii is taken from the outdoors. If the outdoor temperature should fall, it will be apparent that the taking of a large amount of th s cooler outdoor air might result in making the building too cold. Such a fall in outdoor temperature is accompanied by movement of contact arm 229 along outdoor summer resistance 239 towards the right hand end thereof. This will cause solenoid 22l to become more highly energized than solenoid 222, whereupon arm l9l will be moved downwardly. Outdoor damper 92 will therefore be rotated in a counter-clockwise direction towards its vertical position and return air damper 93 will be rotated in a clockwise direction towards its horizontal position. In this manner, if the outdoor temperature decreases in the summer from an intermediate temperature of 70 F. the amount ofoutdoor air taken into theair conditioning chamber II will be gradually reduced until no outdoor air whatsoever is taken therein when the outdoor temperature falls to F. At the same time, the amount of return air is increased from zero to its full flow. When the outdoor temperature rises so that contact am 229 moves along outdoor summer resistance 23!! towards its left hand end. soleno d 222 is more highly energized than solenoid 22! which results in upward movement of arm .I 9 I. This causes clockwise movement of outdoor air damper 92 and counter-clockwise movement of return air damper 93. Therefore, whenever the outdoor tempera-. ture rises above F.. the amount of outdoor air taken into air conditioning chamber II will be gradually decreased and when the outdoor temperature reaches F., no outdoor air whatsoever will be allowed to pass through air cond tioning chamber II but all return air will be culated therethrough.

In this manner, in the summer when the outdoor temperature is approximately that desired within the building, no air will be recirculated and all of the air supplied to the building will be fresh outdoor air. However, if the outdoor temperature rises. or falls below that desired within the building, the amount of outdoor air taken into the building will be decreased. At some undesirable low temperature such as 65 F. and at some undesirable high temperature such as 80 F. all return air will be circulated and there will be no outdoor air or fresh air taken into the building.

As in the winter time, it may be desirable to take in some fresh air irrespective of how high the outdoor temperature becomes. This can be accomplished by again moving rheostat 239 to its dotted position. When this is done, it will be impossible for the outdoor summer thermostat 2-29 to completely close of! the outdoor air inlet duct upon rise in outdoor temperature in the same mannerthat the outdoor winter thermostat is incapable of completely closing off the outdoor inlet duct upon a fall in outdoor temperature whenthe rheostat 299 is adjusted in this same manner.

It should be noted that by means of the use switch operators 399 and 391. 'erator 399 is adapted to operate a limit switch of external resistance in the-form of rheostat 239 during the winter operation, the inlet dampers 92 and 93 are restricted to a 99 angular degree movement which in this particular embodiment of the invention means that the outdoor air supplied may be varied from zero to a maximum upon outdoor temperature change in a single direction. However, in the summer, by the elimination of this external resistance, the inlet dampers 92 and 99 are permitted to move through 180 angular degrees which means in this embodiment of the invention that the outdoor air may be varied from a minimum at low outdoor temperature to a maximum at a desired outdoor temperature and continue on to a minimum at high outdoor temperatures all as a result of temperature change in one direction. It is to be noted particularly that the transition from angular degree operation in the summer to angular degree operation in the winter is accomplished entirely by the insertion of or the exclusion of the proper resistance which having once been determined need never be changed. The change-over from summer operation to winter operation requires only the operation of a reversing switch and no change in linkage between the dampers and the controlling mechanism I99 or any other changes are necessary.

The outlet mixing damper 99 is carried by a shaft 299 to which is secured a pulley 299. This mixing damper 99 is controlled by a mechanism generally indicated at 291 which mechanically is a duplicate of the mechanism I99. The outlet damper mechan sm 291 comprises a. vertical movable actuator 299 which operates an arm 299, pivoted at 299. The lower end of actuating rod 299 is provided with teeth 29I which are engaged by a pinion 292 carried by a shaft 293. 293 further carries a pair of gears 294 and 299. Gear 294 meshes with a pinion 299 secured to the rotor shaft 291 of a motor 299. Motor 299 comprises a rotor 299 and a field winding 999. Similarly, gear 295 meshes with a pinion 99! secured to the rotor shaft 392 of a motor 399. Motor 993 includes a rotor 399 and a field winding 395. Shaft 293 also carries a pair of limit Limit switch op- 399 while limit switch operator 391 is adapted to operate a limit switch 399. Shaft 291 also carries a balancing contact arm 9 which is adapted to sweep back and forth across a balancing resistance 9i I.

The mechanism 291 is adapted to be controlled herein by a potentiometer thermostat H2 or by a manually operable potentiometer M9. The potentiometer thermostat 3|2 comprises a bimetallic actuator9l9 that operates a contact am 315 which sweeps back and forth across a control resistance 3l9 upon changes in the temperature to which thermostatic element 9 responds. In the particular embodiment of the invention herein shown, the thermostat 9l2 responds'to changes Shaft in basement air and contact arm 3I5 engages the IN by means of which the relation of resistarice 9i9 to balancing resistance 3 may be reversed. The summer-winter switch 9" comondary MI by wires 343, 350, 351 and 345. Balance 3H.

the summer-winter' switch 3i8 is thrown to its summer position switch arm 3l9 engages contact 323 and switch arm 320 engages a'contact 324. Contact 326 is connected to contact 324 by a wire 325 and contact 322 is connected to contact 323 by a wire 326.

The manual rheostat 3l3 comprises a resistance 321 and a manually operable contact arm 328. The resistances 316 and 32'! control a pair of solenoids 329 and 330 having their adjacent .ends interconnected, this junction being indicated at 33E. These solenoids 329 and 330 control the position of a plunger 332 that is connected to a relay switch arm 333 through connecting means 33 5. Switch arm 333 is adapted to selectively engage a pair of contacts 335 and 333. The controls for mechanism 237 also include a manually operable switch that includes a switch arm 33? adapted to engage a contact 338 or a contact 339 suitable line wires. One end of field winding 3'00 is connected to secondary 344 through limit switch 308 by wires 393 and 334. One end of field winding 305 is connected to the other side of secondary 33! through limit switch 309 by wires 345 and 346. The other ends of field windings 300 and 395 are connected to relay switch arm 333 by wires 34?, 34B, and 349. The solenoids 329 and 330, in series, are connected across secancing resistance 3!! is connected in parallel with solenoids 329 and 330, in series, through protective resistances 352 and 353 by wires 35%, 355, 356 and 351., The left hand end of balancing resistance 3H is connected to switch arm 320 and to.

the left end of manual resistance 32? by wires 358, 359 and 360. The right hand end of balancing resistance 39! is connected to switch arm 3E9 and the right hand end of manual resistance 327 by wires 36B and 362. The left hand end of control resistance M6 is connected to contact 324 by a wire 363 and the right hand end thereof is connected to contact 323 by a wire 364. The junction 33! of solenoids 329 and 330, balancing contact arm 3l0 and manual switch am 337 are interconnected by wires 365 and 366. Contact 338 is connected to thermal element 3l4 by a wire 361. A small number of turns of solenoid 329 is connected to contact 336 by a wire 368 and a small number of turns of solenoid 330 is connected to contact 335 by a wire 369.

A cable 310 is threaded over pulley 286 and has one of its ends connected to arm 289, whereas its other end is connected to a weight 3' Operation of outlet air mixing damper 96 The parts are shown in their winter position wherein switch arms ,3l9 and 320 of summer-' left hand end of control resistance 3l6 is connected to the right hand end of balancing resist- The manual switch 331 is engaged with contact .338 whereby contact arm 3I5 is connected to balancing contact finger 3| and junction 33L The thermostat H2 is therefore in araaeu a control of the damper operating mechanism 281. The basement temperature is intermediate or about 69 F. since contact arm M5 is engaged with the middle portion of basement resistance 3l6. This basement resistance M6 and the manual resistance 32'! and the balancing resistance 3 all have the same value and all are uniformly wound. Therefore, balancing contact finger 3l0 is engaged with'the mid-portion of balancing resistance 3 and the arm 289 is intermediate its limits of movement. The damper 96 is in its mid-position allowing equal fiows of air through room duct 94 and basement duct 95. It will benoted that damper 96 can only move through 90 and since arm 289 has the same range of movement as arm. HM, and since the cables 310 and l93 are connected to arms 289 and l9| the same distance from the pivotal points 290 and I92, the pulley 286 must be twice'as large as the pulleys H9 and B83 in order that damper 96 will only move through this 90 angular degrees for the complete movement of arm 289.

Now if the basement temperature should fall, contact arm 355 will move along basement resistance 3I6 towards the right hand end thereof. This will cause solenoid 330 to become more highly energized than solenoid 329 whereupon plunger 332 moves to the right and relay switch arm 333 engages contact 335. Field winding 305and the small number of turns of solenoid 330 in parallel are thereby placed in series with field winding 300 by the following circuit: secondary 34l of transformer 340, wire 343, wire 344, limit switch 308, field winding 300 and wire 34! at which point the circuit branches, one part going by way of wire 348, field winding 305, limit switch 309, wire 346, and wire 345 to the other side of secondary 3, whereas the other part goes by way of wire 349, relay switch ar'm 333, contact 335,-wire 369, the small number of turns of solenoid 330, wire 35l and wire 345 to the same side of secondary,

in a counter-clockwise direction as viewed from the left, causes shaft 293 to rotate in a clockwise direction. Balancing contact arm 3l0 therefore moves along balancing resistance 2 ll towards the right hand end thereof until the energizations of solenoid 329 and 330 are rebalanced as previously explained in connection with the mechanism I89. This movement causes upward movemerit of actuating rod 288 and arm 289 whereupon mixing damper 96 is rotated in a clockwise direction to cause a larger'delivery of air through the basement outlet duct 95. In the event the basement temperature should fall to 68 F. so that contact arm 3l5 engages the extreme right hand end of basement resistance 3|6, the arm 289 will be moved to its upper limit of movement and mixing damper 96 will completely close off room outlet duct 94 whereby all of the air from air conditioning chamber II will be delivered through the basement duct 95.

Whenever there is a rise in basement temperature, contact arm 3l5 will move along basement resistance 3l6 towards the left hand end thereof whereby solenoid 329 will be more highly energized than solenoid 330. Plunger 332 will therefore move to the left and bring relay switch arm 333 into engagement with contact 336. places asmall number of turns of solenoid 329 in parallel with field winding 300, the .full current flow traversing field winding 305 by a circuit as follows: secondary 3 of transformer 340, wire 345, wire 346, limitswitch 309, field This 9,143,831 winding m and wire at at which point the circuit branches, one point going through wire 341, field winding 333, limit switch 338, and wire 344 to wire 343 and the other side of secondary 3 while the other part goes by way of wire 349, switch arm 333, contact 333, wire 333, a small number of turns of solenoid 329 and wire 333 to wire 343 and the same side of secondary 3. Motor 333 is therefore more highly energized than motor 293 and its rotor rotates in a clockwise direction as viewed from the left. Shaft 293 is thereby rotated in a counter-clockwise direction and balancing contact arm 3|3 moves along balancing resistance 3 towards the left-hand end thereof. This movement continues until the energizations of solenoid windings 329 and 333 have been rebalanced in a manner heretofore set forth.- Such movement of shaft 293 is accompanied by downward movement of actuating rod 288 and arm 239 whereby damper 93 is rotated in a counter-clockwise direction to diminish the flow of air through basement outlet duct 95 and to increase the flow through room outlet duct 94. If the basement temperature increases to 73 F., contact arm 3|5 will engage the extreme left hand end of basement resistance 3| 3 in order to rebalance the solenoids 329 and 333. Balancing contact finger 3| 3 will therefore move to the extreme left-hand end of balancing resistance 3 and arm 289 moves to its lowermost position rotating damper 93 in a counter-clockwise direction until it is horizontal and completely shuts off all flow of air through basement outlet duct 95.

Inthis manner, if the basement temperature varies from 68 F. to 70 F. in the winter; the flow of air through basement outlet duct 95 is di- -minished from a maximum to no flow whatsoever. correspondingly, the flow of air through the room outlet duct 94 is increased from no flow contact 324, the right hand end of' basement resistance 3 l3 will be connected to the right hand end of balancing resistance .3 and the left hand end of basement resistance 3|3 will be connected to the left hand end of balancing resistance 3| I. In other words, movement of summer-winter switch 3|8 from its winter position to its summer-position reverses the connections of basement resistance 3|3. As a resuit, in the summer when the basement temperature varies from its minimum 68 F. to its maximum 70 F. the flow of air through basement outlet duct 95 will be increased from no flow whatsoever to a maximum flow.

Under some conditions, it maybe desirable to manually control the mixing damper 93 irrespective of temperature conditions in the basement. Under such conditions, manual switch arm 331 is moved from engagement with contact 338 and into engagement with contact 339. This disconnects contact arm 3|5 from balancing contact arm 3|3 and junction 33| and connects manual contact arm 328 therewith. The manual rheostat 3|3 is therefore placed in control and the mixing damper 96 may be moved to the desired,

position by manual manipulation of contact arm 328 irrespective of the prevailing basement temperature. v

In both the mechanisms I89 and 281, the limit switches and actuators are provided in order that the movement of arms I 9| and 289 may be limited if desired. Such limit switches of an adjustable nature are well-known in the art and their utility herein will be appreciated without further explanation.

The protective resistances outlined in both of these systems prevent a complete short-circuiting of the solenoid coils when the controlling contact arms move to an extreme position so as to result in movement of the balancing contact arms in the opposite extreme position.

Fora more complete understanding of modulating systems of this general nature, reference may be had if desired to the copending application of Lewis L. Cunningham, Serial No. 673,236 which was filed May 24, 1933.

Winter operation of the complete system Returning now to Fig. 1 of the drawings, the parts are shown in their winter operating position and operating on the day cycle. The room or space temperature is'at or above the desired minimum since contacts 23 of room thermostat 23 are open. The boiler pressure is below the permissible maximum since low pressure contacts 52 of mercury switch 5| are closed. The pilot 23 is operating properly and bimetallic element 53 is in engagement with contact 59. The boiler water level is sufliciently high as indicated by low water cut-ofl switch 51 being in closed position. Gasvalve I8 is closed so no fuel is being supplied to main burner l1, and valve [3 is open. 4

Power is supplied to certain parts of the system by a hot line 315 and a ground line 313. The winding 19 of the timer motor is constantly energized by a circuit as follows: hot line 315, wire 311, wire 318, and timer motor winding 19 to ground. Timer switch 82 is in closed position since the system is operating on the day cycle. Relay coil 13 of relay 12 is. therefore energized as follows: hot line 313, wire 311, wire 383, wire 33l, timer switch 82, wirei382, wire 333 and relay coil 13 to ground. Switch arm 13 is therefore engaged with contact 13 whereby blower 1| is energized as follows: line 384, switch arm-15, contact 13, wire 385, wire 333, blower 1|, wire 381, and line 388. Air is therefore being drawn into air conditioning chamber through outdoor air inlet duct 93 and return air inlet duct 9| in proportions determined by the settings of dampers 92 and 93 which settings are controlled by the outdoor winter thermostat 223 in the manner heretofore explained in detail. This air passes over preheat coil l2, water spray 93, refrigerating coil 33, reheat coil l3, and is delivered to the rooms and basement in proportions determined .by the setting of damper 93, the setting of which is determined by basement thermostat 3|2 or manual rheostat 3|3 in the manner heretofore described in detail. The refrigerating coil 33 of course is inoperative in the winter as will become apparent when the summer operation is described. Engagement of switch arm 15 with contact 13 of relay 12 conditions water valve 88 which is controlled by the humidostat 89 for operation. Whenever the relative humidity becomes too low, water valve 88 will be energized asfollows: line 384, switch arm 15, contact 13, wire 385, wire 389, water valye 88, wire 393, humidostat 89, wire 39| and line 388. It will therefore be apparent that whenever air conditioningblower 1| is energized, the water valve 88 may be energized under the command of the ing through air conditioning chamber may be humidified v When the room temperature falls below the desired value, contacts 23 of room thermostat M will close and energize relay coil 39 of relay 29 as follows: secondary 31 of transformer 38, wire 392, contacts 23, wire 393, contact 21, switch arm 26, wire 394, relay coil 39, and wire 395 to the other side of secondary 31, it being noted that the primary 39 of transformer 38 is permanently connected to suitable line wires. Energization of relay coil 39 attracts its armature M which in turn moves switch arms 32 and 35 into engagement with contacts 34 and 36 and at the same time moves switch arm 32 from" engage ment with contact 33. Engagement of switch arm 35 with contact 36-energizes primary 59 of transformer 55 as follows: hot line 335, wire 399, contact I64, switch arm I59, wire 39?, contact 39. switch arm 35, wire 398, switch arm I 52, contact I 65, wire 399, wire 499, low water out off switch 51, wire 49I, wire 492, and primary 59 to ground. Engagement of switch arm 32 with contact" 34 energizes energizing coil 4i of relay 49 as follows: secondary 54 of transformer 55, wire 493,

contact 59, bimetallic element 58, wire 494, wire 495, contact 34, switch arm 32, wire 495, low pressure contacts 52 of high limit switch 55,

wire 49?, energizing coil M of relay 49, wire 999,

and wire 499 to the other side of secondary 59. Energization of energizing coil attracts armature 43 which moves switch arms 44 and 45 into engagement with contacts 49 and 41 respectively. Engagement of switch arm 44 with contact 48 establishes a holding circuit for energizing coil 4i which is independent of the low pressure contacts 52 of high limit switch 5i and is also independent of switch arm 32 andcontact 34 of relay 29. This holding circuit is as follows: secondary 54, wire 493, contact 59, bi-

metallic element 58, wire 494, wire 4I9, switch arm 44, contact 46, energizing coil 4!, wire 499,

' and wire 499 to the other side of secondary 54. Engagement of switch arm 45 with contact 41 energizes gas valve I9 as follows: hot line 315, wire 396, contact I54, switch arm I69, wire 391, contact 35 and switch arm 35 of relay 29, wire 398,

switch arm I82, contact I65, wire 399, wire 499.

low water out ofl switch 5I,'wire 49I, wire I, contact 41, switch arm 45, wire M2, and gas valve I8 to ground,

Gas valve I8 therefore-opens and allows fuel to be delivered toJnain burner I I. This fuel is ignited by pilot burner 29 and combustion thereof generates steam or increases steam pressure in boiler I4. This steam passes by way of pipe I5 through the open valve I 5, to reheat coil I3 and then back to the boiler in the usual manner. Some of this steam will also pass through steam valve 9 to preheat coil I2 and back to the boiler provided the outdoor temperature is such that steam valve 9 is open as previously explained.

As a result, the air which is passing throughair conditioning chamber II will be heated and this heated ,air will paste the rooms and to the basement in proportions determined by the setting of mixing damper 95.

In the; event the steam pressure becomes excessive, low pressure contacts 52 of high limit switch 5I will be opened and the high pressure netic field established by bucking coil 42 equalizes that established by energizing coil 4I whereupon armature 43 will return by gravity to the position shown in the drawings, whereupon the circult to gas valve I8 is-interrupted at 454I. After the steam pressure drops a predetermined amount, depending upon the differential setting .of high pressure responsive switching mechaany time, the circuit from secondary 54 of transformer 55 willv be interrupted resulting in demergization of gas valve I8 if it should be energized at that time or prevent energization of gas valve I9upon a subsequent call for heat. If the water level in the boiler should become too low so as to open low water out off switch 57!, the energizing circuit for the primary 53 of transformer 55 as well as the direct operating circuit for gas valve It will be interrupted thereby pre venting initial energization or the continued ensergization of gas valve 65.

After a time, the room temperature will be restored and thermostat 2i will move to the position shown in the drawings interrupting the energizing circuit for relay 29 whereupon switch arm 35 will move from engagement with contact 39 and interrupt the energizing circuit for primary 55' of transformer 55'. The gas valve I 9 will therefore close and remain closed until a subsequent call for heat.

It will be noted that there is no basement thermostat having a direct control over the gas valve I8. However, when the basement becomes cold, the damper 96 is moved toward vertical position 'so as to divert more of the air passing through ment thermostat 3| 2 has an indirect controlover the gas valve I8.,

If a time switch such as switch 82 is used, then when this switch opens the previously described energizing circuit for relay coil I3 01 relay I2 is interrupted. The blower II therefore ceases operating and the humidostat 89 can no longer energize water valve 88. Now if the room should become cold, the gas valve I8 will be energized in the same manner previously explained. Steam pressure will therefore be produced and when this steam pressure becomes sufficiently high, say 2 lbs., bellows 83- will move mercury switch '85 to closed, circuit position whereupon relay coil I3 is energized as follows: hot line 315, wire 3'", wire 389, wire 4I5, mercury switch 85, wire 4I6, wire 383, and relay coil I3 to ground. therefore, blower II is only operated when there is sufiicient steam and in general this sufliciency of steam will only be present as a result of a call for heat by the room thermostat 2 I. During the night cycle whenever the blower ii is operating then the humidostat 89 is again placed incommand of the water valve 39. 1

Summer operation of the complete system For summer operation, the manual steam valve 55 located in the steam supply pipe 55 is closed When operating on the night cycle and the various summer-winter switches are thrown to their summer position. The air conditioning blower 1| will be operated continuously while the time switch 82 is closed by means of the circuit heretofore described in connection with the summer operation. Likewise, the water valve 88 which controls the flow of water to the water spray 86 will be under the control of humidostat 89.

If the temperature of the room or space rises above 70 F. room thermostat 2| will move to its hot position as shown in Fig. l of the drawings,

wherein its'contacts 24 are closed. If the outdoor temperature is also at or above 70 F. the thermostat 22' will be closed so there will be an energizing circuit for relay coil 38 of relay 29 which is as follows: secondary 31 of transformer 38, wire 392, contacts 24 of thermostat 2I, wire 425, contacts of outdoor thermostat 22, wire 426, contact 28, switch arm 26, wire 394, relay coil 38 and wire 395 to theother side of secondary 31. Energization of. relay coil 38 moves switch arms 32 and into engagement withcontacts 34 and 36. Engagement of switch arm 35 with contact 36 energizes relay coil I34 of condenser pump relay I33 by a circuit as follows: hot line 315, wire 311, wire 388, wire 38l, timer switch 82, wire 382, wire 421, contact I61 and switch arm I68 of summer-winter switch I63, wire 391,

contact 36, switch arm 35, wire 398, switch arm I62 and contact I69 of summer-winter switch I63, wire 428, wire 429 and relay coil I34 to ground. Energization of relay coil I34 moves switch arm I36 into engagement with contact I31 to energize condenser pump I3I as follows: line 438, switch arm I36, contact I31, wire 43I, condenser pump I3I and line 432. Operation of condenser pump I 3| will produce a vacuum in condenser I38 and when this vacuum reaches approximately 26 inches of mercury the vacuum re- 7 sponsive switching mechanism I38 will allow mercury switch I to move to closed circuit position whereupon primary 56 of transformer 55 is" energized as follows: hot line 315, wire 3'l1, wire 388, wire 38I, timer switch 82, wire 382, wire 421, contact I61, switch arm I88, Mm 391, contact 36, switch arm 35, wire 398, switch arm I62, contact I69, wire 428, vacuum switch I, wire 433, wire 488', low water cut oil switch 51, wire 48I, wire 482, and primary 56 to ground. Energization of transformer 55 results in opening of gas valve I8 provided the pilot switch 58-59 is closed and provided the steam pressure in boiler I4 is not excessive as heretofore explained in connection with the winter operation.

In the summer time, primary I8I of trans-' former I88 is constantly energized by a circuit as follows: hot line 315, wire 396, contact I64, wire I66, switch arm I6I, contact I68, wire 434 and primary I8I to ground. Therefore, as soon as the steam pressure is built up to 13 lbs. to cause movement of pressure switching mechanism I84 to close its high, pressure contacts, steam valve 98 will be energized to move the same to open position provided the temperature of steam jet injector is within predetermined limits which will be explained in more detail hereinafter. This energizing circuit for opening steam valve 88 is as follows: wire 435, the low temperature contacts of high temperature switching mechanism I86, wire 436, the

high temperature contacts of the low temperanoted that the secondary 99 of transformer I 88 is constantly connected to valve 98 by'wires 438,,

and 448. Opening of steam valve 98 allows steam to flow to the steam Jet injector 6| by means of which the evaporator 44I thereof is cooled in a well-known manner. Opening of steam valve 98 also lifts lever I82 which carries mercury switch I83 whereby mercury switch I83 is moved to close position. Movement of mercury switch I83 to closed position energizes circulating pump relay 66, cooling tower circulating pump relay I48 and cooling tower blower relay I53. These circuits 'are as follows: hot line 315, wire 396, contact I64, wire I66, switch arm I6I, contact I68, wire 434, wire 442, mercury switch I83, wire 443, at which point the circuit branches, one part going by way of wire 444 to relay coil 81 and to ground, whereas another portion continues by wire 445 to relay coils I49 and I54 and to ground. Energization of relay coil 61 moves switch arm 69 into engagement with contact 18 whereupon cooling circulating pump 65 is energized as follows: line 446, switch arm 69, contact 18, wire 441, pump 65, and line 448. Operation of this pump 65 circulates the cooling fluid through the evaporator I and to the cooling coil 68. Energization of relay coil I49 moves switch arm I5I into engagement with contact I52 and energizes this cooling tower water pump I44 as follows: line 449, switch arm I5I, contact I52, 'wire 458, cooling tower pump I44 and wire 45I. Energizationof cooling tower pump I44 causes circulation of the condenser cooling water through the condenser cooling coil I42 and then to the water tower spray I43. Energization of relay coil I54 moves switch arm I56 into engagement with contact I51 whereupon cooling tower blower I41 is energized as follows: line 452, switch arm I56, contact I61, wire 453, cooling tower blower motor I41 and line 454.

In this manner, when the room becomes too warm in the summer and provided that the outdoor temperature is not below the desired room temperature, a proper vacuum is placed upon the steam jet injector and, when this proper vacuum is established, the gas valve I8 is energized to generate steam. When the steam pressure becomes, sufliciently high, steam valve 98 is opened to supply steam to the steam jet in- ,iector and the various pumps and blowers are placed in operation. Delivery of steam to the steam jet injectorcauses the evaporator 44I thereof to become cool and this in turn cools the cooling fluid which is circulated to the cooling coil 68 by thecirculating pump 65. The steam introduced to the steam jet injector 6I thereafter passes to condenser I38 where it is condensed and returned to the boiler by vacuum pump I3I. The condensing operation is obtained by the usual condenser cooling coil I42 and the condenser cooling water may be used over and over since it is cooled by means of the water tower I45. The pump I44 serves to cause circulation of the condenser cooling water and, as heretofore explained, the water tower blower. I41 provides an increased rate of evaporation so that the condenser cooling water is cooled more readily.

The air passing through air conditioning chamber II is therefore reduced in temperature in order to restore the room or space temperature to the desired value. The air passing into the air conditioning chamber II will be taken from the outdoors and from the building in amounts which are determined by the positions of inlet dampers 92 and 93 which are controlled in the manner approximately 10 lbs.

heretofore set forth in detail. Similarly, the air passing through air conditioning chamber I I is delivered to the rooms and to the basement in accordance with the position of mixing damper 96 which is controlled by basement temperatures in a manner also fully explained heretofore.

If the steam is used up faster than it is being generated, pressure responsive switching mechanism I04 will return to the position shown in the drawings when the steam pressure falls to When this happens, the steam valve 98 is closed by a circuit as follows:

wire 438, the low pressure contacts of pressureresponsive switching mechanism E04 and wire 455. Movement of steam valve 98 to closed position will open mercury switch I03 whereupon the two circulating pumps and the cooling tower blower are deenergized. Upon the steam pressure returning to approximately 13 lbs., the steam valve 98 will again operate by the circuit above described.

It is possible that the temperature of the steam I of freezing thereof and would also oifer the possibility of freezing any spray water which might be delivered from spray 86: Therefore, if the evaporator temperature does fall to some low degree such as F. low temperature responsive switching mechanism I05 will move to the position opposite that shown in the drawings to complete a closi ng circuit for steam valve 98 as follows: wire 438, high pressure contacts of pressure responsive switching-mechanism E04, wire 631,

wire 456, and wire 455. The cooling apparatus will therefore-be rendered inoperative until the temperature of the evaporating chamber rises to some higher value say 45 F., whereupon the opening circuit for steam valve 98 heretofore de-- scribed will be reestablished.

If the steam jet injector should not function properly resulting in steam backing up into the evaporator I so that the temperature thereof becomes so high as to render it incapable of cooling the circulating cooling fluid, then high temperature contacts of high temperature responsive switching mechanism I06 will close to establish a closing circuit for the steam valve 98' as follows: wire 4 38, high pressure contacts of pressure responsive switching mechanism I04, wire 431, high temperature contacts of low temperature responsive switching mechanism I05, wire 636, the high temperature contacts of high temperature :5- sponsiveswitching mechanismI06, wire 451 and wire 456 to wire 455. Steam valve 98 will therefore close and the cooling system rendered inoperative until the evaporator temperature returns to normal whereupon steam valve 98 will again be opened by the'opening circuit previously described. a v

It will therefore be seen that the operation of the cooling system in the summer time is completely checked for all conditions of improper operation. The vacuum switch I assures that there is a proper vacuum in the steamsystem so that the steam jetinjector will operate properly.

The pressure responsive switching mechanism I94 prevents operation of the steamjet injector unless the steam pressure is sui ilciently high. The low since steam cannot be generated unless there is a proper vacuum. However, it may happen that the vacuum is less than the desired 26 inches of mercury and at the same time there may be suiiicient steam pressure to cause opening of the steam valve 98. If it is desired to eliminate this remote possibility, the vacuum responsive switching mechanism I38 may be removed from in circuit with primary 56 of transformer 55 and placed in circuit with the steam valve 98, such a change requiring a double-ended mercury switch rather than the single-ended mercury switch shown. Such a change in connections might have the further advantage of allowing the vacuum to be produced and steam pressure generated concurrently so that the proper vacuum and the proper steam pressure would be established more quickly upon a demand for cooling by the room thermostat.

The outdoor thermostat 22 normally will not come into play in the operation of the system but in the event the room temperature is slightly above that desired and th re is a sudden fall in the'outdoor temperature, t en the thermostat 22 will prevent operation of the cooling means since it is evident that circulation of outdoor air will soon restore the room temperature to that desired without resorting to operation of the cooling means. v

At night, the system will be completely out of operation since time-switch 82 will open and the pressure responsive switching mechanism I8 is inoperative by reason of closure of manual valve I5. As heretofore explained in connection withthe winter operation, the time switch 82 is only used where the air conditioning system of the present invention is being utilized in conjunction with office buildings and the like. If the system of the present invention be applied to buildings or residences which are in continuous use and wherein it is desired to have full twenty-four hour control, then the time switch 82 would be omitted.-

From the foregoing description, it will be apparent that the present invention provides an all year around air conditioning system wherein the building is heated, cooled, andhumidified as necessary. It will further be noted that both in the summer and the winter a reasonable amount of outdoor fresh air is brought into the building whenever the outdoor temperature is such as to permit such operation. Furthermore, the cooling means and the heating'means are both operated by the same medium, that is, by

steam. Furthermore, this steam is produced by a single boiler under the control of suitable controls, many of which serve the double function of controlling both in summer and in winter. The system of the present invention further provides for many other novel features in its operation which have previously been brought out during the detailed description.

While a plurality of separate summer winter switches have been shown, it is to be understood'that in actual practice these various summer winter switches could all be grouped together and operated by a single control handle. The

separation of these switches has been shown herein merely for convenience of illustration. It will also be apparent that the valve it could be an electrical valve controlled by a further part of the summer winter switching mechanism.

It will be obvious that many changes and rearrangements could be made in the system of the present invention without departing from the various novel features contained herein and we therefore intend to be limited only by'the scope of the appended claims.

We claim:

1. An all-year air conditioning system oi the class described, comprising, in combination, a steam heating device for heating a space, a steam jet injector type of cooling means for cooling said space, a steam boiler for supplying-steam to said steam heating device and steam jet injector type or cooling means, thermostatic means in control of the generation of steam by said boiler, means associated with said thermostatic means to selectively cause the generation of steam by said boiler upon either a rise or fall in temperature and means for selectively sending the steam generated by the boiler to said heating means or cooling means.

2. An all-year air conditioning system of the class described, comprising, in combination, a steam operated heating means for heating a space, a steam operated cooling means for cooling the space, a steam boiler for generating steam to operate said heating means or cooling means, a space temperature responsive thermostat, an outdoor temperature responsive thermostat, means to place said space temperature responsive thermostat alone or to place both 0! said thermostats in control of said boiler, a' steam valve in control of the flowoi? steam to said cooling means, and means for rendering said steam valve operative or inoperative.

3. In a temperature changing system, in combination, a temperature changer for changing the heat content of air adapted to be circulated to first and second spaces, damper means in control of the flow of air to both of said spaces to simultaneously increase the flow of air to one of said spaces and decrease the'flow of air to the other of said spaces, a -thermostat responsive to the temperature of only one of said spaces in control of said damper means, and a thermostat responsive to the temperature of the other oi! said spaces in control of said temperature changer,

4. In a temperature changing system, in combination, a temperature changer for changing the heat content of a circulating fluid adapted'to change the temperature of first and second spaces, a thermostat responsive to the temperature of one of said spaces in control of said temperature changer, circulation controlling means in control of the respective flow of fluid to said two spaces to simultaneously increase the flow to one and decrease it to the other, a thermostat responsive to the temperature of the other of said spaces in control of said circulation controlling means, and means for reversing the operation of said circulation controlling means by said last which minimum outdoor air is circulated to said space an outdoor winter thermostat for controlling said damper means to move the same from said second position to one of said other positions upon a predetermined decrease in outdoor temperature and incapable of moving said damper means to the remaining position, an outdoor summer thermostat in control of said damper means for moving the same from its first position through its second position and to its third position upon a predetermined rise in the outdoor temperature, and means for selectively placing one or the other of said thermostats in control of said damper means.

6. In a temperature changing system for a space, in combination, a duct connecting said space to the outdoors, a damper pivoted therein and movable through approximately 180 angular degrees whereby upon movement of said damper from one of its extreme positions to its other extreme position the supply of outdoor air is in creased from a minimum to a maximum and then decreased to a minimum, motor means connected to said damper, said motor means having a complete range of movement capable of moving said damper through said approximate 180 angular degrees, a first thermostat adapted to move said motor means through the larger part of its range, a second thermostat adapted to move said motor means through a substantially smaller part of its range, and means for selectively placing one or the other of said thermostats in control of said motor means. I

7. A heating system of the class described,comprising, in combination, means for circulating outdoor air to aspace to be heated, damper means in control of the circulation of said air, a first heater, a space thermostat in control thereof, a second heater, and outdoor temperature infiuenced thermostatic means in control of said damper means for reducing the supply of outdoor air and for rendering said second heater operative at a predetermined minimum outdoor temperature.

8. A heating system of the class described, comprising, in combination, means for controlling the circulation'of outdoor air to a space, first and second heaters for heating said air, a space thermostat in control of said heaters, and outdoor temperature influenced means for reducing the supply of outdoor air and for conditioning one of said heaters for operation by said thermostat when the outdoortemperature falls to a predetermined value,

9. A heating system of the class described, comprising, in combination, a chamber, means for circulating air therethrough, a steam heater located vin said chamber for heating the air circulated therethrough, a space thermostat in control of the supply of steam to said heater, a time control for rendering said circulating means inoperative at predetermined times, and a steam pressure responsive device for operating said circulating means when the pressure of the steam supplied to said heater rises to. a predetermined value irrespective oi the condition of said time control.

10. A heating system of the class described, comprising, in combination, a chamber, means for circulating air therethrough, a steam heater located in said chamber for heating the air there through, a space thermostat in control of the supply oi. steam to said heater, a time control for rendering said circulating means inoperative at predetermined times, and a steam pressure responsive device for operating said circulating means when the pressure of the steam supplied to said heater rises to a predetermined value irrespective of the. condition of said time control,

means for humidifying the air passing through, said chamber, a humidity responsive device adapted to control said means, and connections for rendering said humidity responsive device operative whenever said circulating means is circulating air through said chamber.

11. A heating and cooling system, comprising, in combination, aboiler for generating steam, a space temperature responsive thermostatic means, an outdoor temperature responsive thermostatic means, means to place said space temperature responsive thermostatic means alone in control of said boiler to cause generation of steam upon space'temperature fall or to place both said thermostatic means in control of said boiler to cause generation of steam upon rise in both space temperature and outdoor temperature, steam operated heating means, steam operated cooling means, and means to selectively operatively associate either said heating means or said cooling means with said boiler.

12. In a heating system, in combination, means for controlling the circulation of fresh air to a space to be heated, damper means in control of the flow of fresh air to the space, motor means to graduatingly position said damper means, means responsive to outdoor temperature in control of said motor means to cause movement of said damper means in a direction to reduce the flow of fresh air to said space upon fall in outof spaces, comprising in combination, air c'onditioning means including heating means, cooling means and means for delivering conditioned air to all or said spaces, means including means responsive to the temperature of the air in at least one of the spaces for'controlling the operation oi-the heating means and cooling means and consequently the condition of the air delivered to all of the spaces, means responsive to the temperature of the air in another 01 said spaces for controlling the volume of conditioned air delivered to said other space, and means for reversing the controlling action of the last mentioned temperature responsive means. 1

1a. In an air conditio system, in combination, a conditioning chamber through which air is adapted to be passed for a conditioning action, means for vconducting the air leaving said conditioning chamber to a space to be conditioned, means for conducting air from said space to said conditioning chamber, a fresh air duct for conducting iresh air to said conditioning chamber, a damper for controlling the supply of fresh air. a heater for heating the fresh air supply, and outdoor air temperature influenced thermostatic means for controlling said damper and said heater in a manner to reduce the supply of fresh airupon ,falls'to a predetermined value.

' i 15. In an air conditioning system, a conditioning chamber, means for causing a new of fresh air through said chamber, an air temperature device in said chambena damper for changing device, and thermostatic means influenced by the temperature of the fresh airfor nected to said damper means for operating thedamper means to vary the flow of outdoor air from. a minimum to a maximum and then to a minimum when the motor means moves through its complete rangein one direction, a first thermostat for moving said motor means through its complete range, a second thermostat for moving said motor means through only a portion of said range, and means for selectively placing said thermostats in control of said motor means. a

17 In an all-year temperature chang system, means for circulating outdoor air to a space, damper means in control of the circulation of outdoor air to said space, motor means con-. nected to said damper means for operating the damper means to vary the flow of outdoor air from-a minimum to a maximum and then to a minimum when the motor means moves through its complete range in one direction a first thermostat for moving said motor means through its complete range, a second thermostat for moving said motor means through only a portion of said range, means for varying therange through which one of said thermostats operates said motor means, and means for selectively placing-said thermostats in control of said motor means.

18. In a system of the class described for controlling the condition of more than one zone, in combination, a condition changer for changing the condition of first and second zones to be controlled, control means for varying the efiect of said condition changer upon both of said zones, said control means being arranged to increase the eiiect of said condition changer upon one of said zones while decreasing the eflject of said condition changer upon the other of said zones and being incapable of placing said condition changer in operation, means responsive to the condition of one of said zones for controlling said condition changer, and means responsive to the condition of the other of said zones for controlling said control means.

19. In a system of the class described for controlling the temperature of more than one zone,

changing the temperature of first and second zones to be controlled, control means for varying the effect of said temperature changer upon both of said zonesQsaid control means being arranged to increase the efiect of said temperature changer upon one of said zones while decreasing the effect of said temperature changer upon the other of said zones and being incapable of placing'said temperature changer in operation, means responsive to the temperature of one of said zones for controlling said temperature changer, and means 'in combination, a single temperature changer for responsive to the temperature of the other of said zones for controlling said control means.

20. In an air conditioning system for controlling the condition of the air in more than one zone, in combination, a single conditioner forc'onditioning air supplied to first and second zones,

flow control means for varying the proportions- 01' the air supplied to said zones, said flow control means being arranged to increase the flow of air to one of said zones whiledecreasing the flow of air to the other 01' said zones, means responsive to the condition of the air in said one of said zones for controlling said conditioner in a manner to maintain a predetermined condition of the air in said one zone, and means responsive to the condition 0! the air in the other of said zones for controlling said control means in a manner to maintain a predetermined condition of theair in said other zone.

\ GEORGE D. KINGBLAND.

JOSEPH E. ROBE. 

